adapter

README.md

@@ -15,8 +15,14 @@
 | [Singleton](/creational/singleton.rs) | Restricts instantiation of a type to one object | ✔ |
 
 
-
 ## Behavioral Patterns
 | Pattern | Description | Status |
 |:-------:|:----------- |:------:|
 | [Strategy](/behavioral/strategy.rs) | Enables an algorithm's behavior to be selected at runtime | ✔ |
+
+
+## Structural Patterns
+
+| Pattern | Description | Status |
+|:-------:|:----------- |:------:|
+| [Adapter](/structural/adapter.rs) | allows objects with incompatible interfaces to collaborate. | ✔ |

structural/adapter.rs

@@ -0,0 +1,70 @@
+use std::rc::Rc;
+
+// The Target defines the domain-specific interface used by the client code.
+trait Target {
+    fn get_request(&self) -> String {
+        String::from("Target: The default target's behavior.")
+    }
+}
+
+struct DefaultTarget;
+impl Target for DefaultTarget {} 
+
+// The Adaptee contains some useful behavior, but its interface is
+// incompatible with the existing client code. The Adaptee needs some
+// adaptation before the client code can use it.
+struct Adaptee {
+    req_str: String,
+}
+
+impl Adaptee {
+    fn new(s: String) -> Adaptee {
+        Adaptee{
+            req_str: s,
+        }
+    }
+    fn specific_request(&self) -> String {
+        format!("specific request: {}", self.req_str)
+    }
+}
+
+// The Adapter makes the Adaptee's interface compatible with the Target's
+// interface.
+struct Adapter {
+    adaptee: Rc<Adaptee>,
+}
+
+impl Adapter {
+    fn new(a: Rc<Adaptee>) -> Adapter {
+        Adapter {
+            adaptee: a,
+        }
+    }
+}
+
+impl Target for Adapter {
+    fn get_request(&self) -> String {
+        format!("Adapter: {}", self.adaptee.specific_request())
+    }
+}
+
+// The client code supports all classes that follow the Target trait.
+struct Client;
+impl Client {
+    fn clinet_code<T: Target>(target: T) {
+        println!("{}", target.get_request());
+    }
+}
+
+
+fn main() {
+    println!("Client: I can work just fine with the Target objects:");
+    Client::clinet_code(DefaultTarget{});
+    let adaptee = Rc::new(Adaptee::new("hello world".to_string()));
+    println!("Client: The Adaptee class has a weird interface. See, I don't understand it:");
+    println!("Adaptee: {}", adaptee.specific_request());
+
+    println!("Client: But I can work with it via the Adapter:");
+    let adapter = Adapter::new(adaptee);
+    Client::clinet_code(adapter);
+}